Lifter knife for loom dobbies



Oct. 29, 1940. E; R. HOLMES 2,219,778

` 'LIFTER KNIFE Fow'noom noBBIEs Filed June 5, 1959 Ii- FIE. E

INvENToR ELmosE R. HoLMs A-r-ronNEY UNI Patented oci. 29, 1940 2,219,778

UNITED STATES PATENT OFFICE LIFTER KNIFE FOR LOOM DOBBIES Elbridge R. Holmes, Worcester, Mass., assgnor to Crompton & Knowles Loom Works, Worcester, Mass., a corporation of Massachusetts Application June 5, 1939, Serial Noi 277,487

3 Claims. (Cl. 139-67) fhis invention relates to improvements in loom dobbies and it is the general object of the invention to provide an improved lifter knife for the harness actuating hooks.

Fig. 1 is a rear elevation of a dobby equipped with my improved knife,

Fig. 2 is an end view taken in the direction of arrow 2, Fig. 1,

5 In the usual dobby the harness lifting hooks Fig. 3 is a vertical section on line 3 3, Fig. 2, 5 are adapted for cooperation with lifter knives Fig. 4 is a diagrammatic plan view looking in which ordinarily reciprocate in opposite directhe direction of arrows 4 4, Fig. 3 showing the tions in spaced horizontal planes. Because of the knife adjacent to the fingers in extreme outward requirement that the rear harness frames shall position,

be lifted higher than the front frames, the rear Fig. 5 is an enlarged transverse section through 10 end of the knife moves more than does thefront the central part of the knife, and end. When in one extreme position the knife Fig. 6 is a perspective view of the improved will be oblique with respect to the hooks in one knife. direction, while in the other extreme position the Referring to Fig. 1, I have shown a loom frame knife will also be oblique but in the opposite di- I Il having two arches II on which is supported 15 rection The position of the hooks is deterthe dobby designated generally at D. The dobby mined by so-called fingers which have direct enis provided with a plurality of harness lifting gagement with the pattern mechanism, and the jacks I2 which are attached to the warp harnesses outer ends of these lingers are generally ennot shown. Each jack has pivoted thereto a larged to provide counterbalance heads which dobby back lever I3 provided with top and bottom 20 over-balance the hooks hooks I4 and I5, respectively. The position of It is an important object of my present lnthe hooks is determined by pattern fingers I6 vention to strengthen the lifter knife by adding which lie over a pattern chain II mounted on a thereto a web or rib so constructed as to provide cylinder I8. The fingers are normally supported additional strength more particularly in the cenby a cross bar I9 of the dobby and are raised by 25 ter of the knife and arranged so that the rib pegs 20 on the pattern chain and fall to resting avoids interference with the heads of the fingers position on the support I9 when no peg is under when the knife assumes its oblique position nearthem. The fingers are arranged in pairs, one est to the finger heads member of each pair having an upstanding end The aligned heads lie in a line perpendicular 2I to have direct engagement with a lower hook 30 to the dobby side frames and form a triangle l5. While the other nger 0f the pair has an end with the oblique knife when the latter is nearest 22 connected by means 0f a Vertical rod 23 to the heads I locate the reinforcing rib in this the' 130D 1100k t0 DOSOD the latter- In Order triangle and find that in doing so the web or rib that the Weight 0f the hcOkS and TcdS may be 85 is wider at a point near the center of the knife counter-balanced cach flgel l5 iS provided with 35 than at the end, thereby giving the knife its a ccuhtclwcght head 24 Which projects upwardly greatest reinforcement at a point where the harfrom the n lam body 0f the finger as mdcated ness lifting strain is greatest, that is, farthest from Clear 1y 1n F1g- 3' the supporting links which support and drive The dobby frame is formed Wlth from and o the knife back side plates 30 and 3I 'through which exo Dobbies are made right and left hand and in ends a rocker shaft 32 drwen by a lever 33 order to provide a knife usable in both kinds of eye? thezeon behmd plate 3|. and having con" dobbies I form the rib widest at the central part gicgnbylle afgigg leotll fr? 34 own of the knife and taper 1t @Ward the ends' Tms manner. Shaft 32 is extended beyond the side 45 retains the greatest reinforcement near the plate 3D to have keyed thereto front lever 35, middle of the knife While permitting either end and these levers rock to th .t

ge er wi h the shaft 32. to bf? at the rear part of the, d0bb-y' Lever 33 has a short upper arm 40 attached Wlth these and other, oplects m new whch by connector 4I to one end of the upper knife Wm appearas the descnptlon Proceeds my m' 42, while upper arm 43 of the lever 35 is attached 50 vention resides in the combination and arrangeby a connector 44 to the front part of knife ment of the parts hereinafter described and set The side plates have laterally project-,lng arms forth- 45 slotted as at 46 to afford sliding support for In the accompanying drawing, wherein a conthe top knife 42. It should be noted that the venient embodiment of my invention is set forth. rear arm 40 is longer than the front arm 43, so 55 that for equal angular motions of the levers 33 and 35 the rear end of knife 42 will move farther than the front end thereof.

In similar manner, lever 35 has a depending short arm 52 driving a connector 53 while the rear lever 33 has a depending arm 50 longer than arm 52 and is attached to connector 5I. Rods I and 53 correspond in function to the upper rods 4I and 44, respectively. The side plates of the dobby are provided with lower laterally extending arm 55 having horizontal slots 56 similar to the slots 46.

The matter thus far described is of common construction and of itself forms no part of my present invention. As the loom operates rod 34 is raised from one pick of the loom to move knife 42 outwardly or to the right as viewed in Fig. l, while on the following pick rod 34 descends to move the knife 42 rearwardly or to the left. Opposite motions occur simultaneously with the bottom knife to be described. The hooks I4 and I5 will either engage or clear their respective knives, depending upon the control exercised over them by the pattern chain.

My present invention relates more particularly to the bottom knife, although the top knife 42 may if desired be formed to include the invention which I will now describe. The bottom knife K comprises an elongated body 60 at each end of which is formed a slide bearing block 6I. From `the forward end of the knife K there projects a gudgeon 63 for cooperation with connector 53, while a second gudgeon 62 projects rearwardly from the back end of the knife for cooperation with the connector 5|. The knife K has a shoulder 64 defining a hoo-k engaging lifter edge 65 of usual form for cooperation with the lower hook I5. The parts of knife K already described are of usual form, bearings 6I sliding in slots 56 as the knife reciprocates by rocking of shaft 34.

My invention relates more particularly to a reinforcement for the knife set forth for instance in Fig. 6 and includes a web or rib 10 integral with the knife body 60 and projecting to the right thereof below the lifter edge 65. The rib 'I0 is low enough to permit proper engagement of the lifter edge 65 with the bottom knives I5. The web is widest at a point midway between the blocks BI and tapers off to a negligible width near said blocks. By this construction the central part of the knife which is farthest removed from the gudgeons 62 and 63 is given additional strength to withstand the effort of lifting the harness frames.

Reference to Fig. 4 may be had to understand the relation between the reinforcing web and the previously described heads of the dobby fingers. In that figure the knife K is indicated in two positions, position I in dotted lines suggesting the angular relation of the knife with respect to the dobby sides when knife K is in its extreme in position or to the left as viewed in Fig. 1. Full line position II, on the other hand, indicates the position of the knife K when I the latter is moved to its extreme outward position. It will be seen that position I is oblique with respect to the dobby sides with the rear end of the knife nearer the dobby back levers I3 than the front end, whereas in position II the knife is also oblique but with the rear end thereof farther from the dobby back levers I3 than the front end. This changing angular relation of the knife will be understood from the fact that the front and back arms of the driving levers are of unequal lengths, the rear arms being longer.

The heads 24 of the fingers I6 are in substantial alignment transversely of the path of motion of the knife K and extend in a row which is more or less perpendicular to the sides 30 and 3|. It will also be seen from Fig. 3 that these heads project upwardly beyond the plane in which lower knife K slides. It is this latter relationship which has an important bearing on the shape of the reinforcing rib 10. It will be seen from Fig. 4 that when the knife is in position II the rear end thereof is close to the aligned heads 24, at the right hand side of Fig. 4, while the front end is spaced farther from said heads. This relationship denes a triangle between the body 60 of the knife and the aligned heads 24. The rib is located in this triangle, the rear end of the rib being of slight or negligible width near the vertex of the aforesaid triangle, and the wider central portion of the rib lying in that part of the triangle approximately midway between the side plates 30 and 3|. By this arrangement the knife is made strongest at its longitudinal center which is farthest removed from the driving links or connectors 5I and 53. The outer edge of the rib near the rear part of the row of aligned heads 24 may be uniformly spaced from the latter, although this is not a necessary relation.

During operation of the dobby the knife K will start on its outward motion from the dotted position I, Fig. 4, in engagement with any hooks which might have been left in lowqposition by the pattern chain. During this outward motion the knife will change its angular relation with respect to the dobby sides and ultimately reach the position II, where it is nearest the aligned head 24. During this outward motion the knife K will be subject to the strain of lifting the harness frames not shown which correspond to the hooks engaged thereby.

As previously stated, dobbies are made right and left hand and in order that the knife set forth herein may be usable in dobbies of both hands I make the reinforcing rib symmetrical so that its ends taper toward the body 60 at points adjacent to the sliding blocks 6I with the widest part of the rib at or near the longitudinal center of the body 60. By so forming the rib I provide a knife which is evenly balanced and wherein the amount of reinforcement added by the rib diminishes from the center toward the ends. For use in any given dobby, however, it is sufficient if one end only of the knife is made with the web formed as described and I do not wish to be limited in the practice of my invention to a rib which is necessarily symmetrical about a central transverse axis of the knife.

From the foregoing it will be seen that I have provided an improved dobby knife having a reinforcing rib which is located between the body of the knife and the linger heads 24 when the knife is in its outermost position II, Fig. 4. Such a construction provides maximum reinforcement for the central part of the knife most distan-t from the supporting gudgeons 62 and 63. It will also be seen that the reinforcement can be shaped so that the knife can be used in both right and left hand dobbies. Furthermore, the upper knife can be the same as knife K if desired. The lifting strain on the knife places a compression strain on the rib and the latter` can therefore be made comparatively small while at the same time adding considerably to the strength of the dobby.

Having thus described my invention it will be seen that changes and modifications may be made 5 therein by those skilled in the art without departing from the spirit and scope of the invention and I do not Wish to be limited to the details herein disclosed, but what I claim is:

1. In a dobby having a set of fingers with heads aligned transversely of the dobby, a reciprocating knife movable toward and from the heads along a path which when projected passes through the heads, an elongated body forming part of the knife and having a hook lifting edge, means to move lthe knife on a working stroke toward said heads and place one end of the lifting edge nearer said heads than the other end of said Ilifting edge at the conclusion of a Working stroke to locate the lifting edge diagonally with respect to the aligned heads, and a reinforcing rib on said body below the lifting edge and projecting from the body toward the aligned heads and located between the latter and the body when the knife is nearest said heads, said rib being narrow at a point adjacent to one end of said lifting edge where the body is near the heads and Wider at a point near the longitudinal center of the lifting edge where the body is farther from said heads when the knife is nearest said heads at the end of a working stroke.

2. In a loom dobby, a reciprocating hook engaging knife movable in a given plane, means to move the rear end of the knife through a greater distance than that through which the front end of the knife moves, a set of dobby ngers having heads projecting across the plane in which the knife reciprocates and aligned in a direction transverse of the direction in which the knife moves, said knife having an elongated body provided with a hook lifting edge, said 5 means moving the knife toward the heads to a position diagonal with respect to the aligned heads, and a reinforcing rib projecting from the body below the edge and toward the heads, said rib being of negligible width near the rear end l0 of the knife and being of greater width at a point near the. longitudinal center of the knife and extending into the space between the heads and the knife.

3. In a loom dobby, a reciprocating hook en- 16 gaging knife movable in a given plane, means to move the rear end of the knife through a greater distance than that through which the front end of the knife moves, a set of dobby fingers having heads projecting across the plane 20 in which the knife reciprocates and aligned in a direction transverse of the direction in which the knife moves, said knife and aligned heads forming a triangle the rear part of which is comparatively narrow and that part thereof ad- 2l jacent to the longitudinal center of the knife being wider than the rear part of the triangle when the knife is nearest to the heads, said knife having a body with an upper hook engaging edge and a rib to reinforce the body projecting from 3 the latter at a point below the lifting edge and extending into the triangle, said rib being of less width near the narrow end of the triangle than at a point where the triangle is wider.

ELBRIDGE R. HOLMES. 

